The present invention has incidental similarity to several kinds of well-known apparatus. The invention has features in common with certain electric signs wherein light bulbs distributed along a preformed pattern of straight and curved lines are briefly turned on and then turned off in succession; such signs have eye-catching appeal and are entertaining. The invention also has points of similarity to common electronic calculators in which there is a keyboard, a display panel of light-emitting diodes (LED's) or a liquid-crystal display (LCD) and control apparatus to display a character corresponding to a depressed key; all of the display elements of any one character are actuated concurrently and they stay "on" after the key is released. Certain displays are used (as destination signs of buses) in which characters are displayed by concurrently actuating selected display elements, column by column of a matrix, as are needed for displaying a succession of characters.